Macbook Pro (airport extreme card)

Been using a Mac for about 2 months now (come from UNIX/[BSD/System 5] & PC environment).

I have a linksys wireless G router with up to date firmware. I have basic security setup; WPA personal / TKIP (wpa algorithym)
I have a PC laptop and a MacBook Pro with up-to-date software installation.
The PC laptop connects to the linkys at a reasonable speed considering the distance from the the access point. The MacBook Pro tends to connect from the same location and then tends to drop out altogether; the signal is unbelievably weak.

The way I see it:
Could be a firmware issue on the airport extreme card.
Could be an airport extreme technical spec issue vs the linksys.

Has anyone experienced similar using the components I've mention? If so, what was the fix?